According to 3GPP (3rd Generation Partnership Project), which is a project aiming to standardize a mobile communication system, a technology for power saving (energy saving), which reduces the power consumption of a network, has been introduced (for example, see Non Patent Document 1). For example, when the communication traffic is less during nighttime, a base station (a cell) is set to the power saving mode.
Moreover, according to 3GPP, in Release 12 and later, an improved energy saving technology is planned to be introduced. For example, it is assumed that in a network deployment (so-called HetNet) in which a plurality of small cells (hot spot cells) are arranged within the coverage of macro cells, the small cells are selectively set to the power saving mode or normal mode in response to the traffic status.